Background and Aim: Understanding and defining developmental norms of auditory comprehension is a necessity for detecting auditory-verbal comprehension impairments in children. We hereby investigated lexical auditory development of Persian (Farsi) speaking children.
Methods: In this cross-sectional study, auditory comprehension of four 2-5 year old normal children of adult&aposs child-directed utterance at available nurseries was observed by researchers primarily to gain a great number of comprehendible words for the children of the same age. The words were classified into nouns, verbs and adjectives. Auditory-verbal comprehension task items were also considered in 2 sections of subordinates and superordinates auditory comprehension. Colored pictures were provided for each item. Thirty 2-5 year old normal children were randomly selected from nurseries all over Tehran. Children were tested by this task and subsequently, mean of their correct response were analyzed.
Results: The findings revealed that there is a high positive correlation between auditory-verbal comprehension and age (r=0.804, p=0.001). Comparing children in 3 age groups of 2-3, 3-4 and 4-5 year old, showed that subordinate and superordinate auditory comprehension of the former group is significantly lower (p<0.05) than the others . Intra-group comparisons revealed no significant difference between nouns, verbs and adjectives (p>0.05), while the difference between subordinate and superordinate auditory comprehension was significant in all age groups (p<0.05).
Conclusion: Auditory-verbal comprehension develop much faster at lower than older ages and there is no prominent difference between word linguistic classes including nouns, verbs and adjectives. Slower development of superordinate auditory comprehension implies semantic hierarchical evolution of words.

Background: Hyperlexia is a super ability demonstrated by a very specific group of individuals with developmental disorders. This term is used to describe the children with high ability in word recognition, but low reading comprehension skills, despite the problems in language, cognitive and social skills. The purpose of this study was to assess the effectiveness of improving the semantic aspect of language (increase in understanding and expression vocabulary) on reading comprehension in an autistic child with hyperlexia.
Case: The child studied in this research was an autistic child with hyperlexia. At the beginning of this study he was 3 years and 11 months old. He could read, but his reading comprehension was low. In a period of 12 therapy session, understanding and expression of 160 words was taught to child. During this period, the written form of words was eliminated. After these sessions, the reading comprehension was re-assessed for the words that child could understand and express.
Conclusion: Improving semantic aspect of language (understanding and expression of vocabulary) increase reading comprehension of written words.